1. Institute of Chemical Sciences, University of Urbino, P.za Rinascimento 6, I-61029 Urbino, Italy, “Sergio Stecco” Department of Energy Engineering, University of Florence, Via S. Marta 3, I-50139 Florence, Italy, and CRIST Centro Interdipartimentale di Cristallografia Strutturale, University of Florence, via della Lastruccia 3, 50019 Sesto F.no, Florence, Italy